X-Message-Number: 15319 Date: Thu, 11 Jan 2001 07:50:00 -0500 From: Thomas Donaldson <> Subject: superficial ideas about computers Again, for Joseph Kehoe: Unfortunately there are problems with your ideas. Perhaps they can be solved, perhaps not... but here goes. First, it's not at all clear that increasing the number of neurons could simply involve growth of new ones from old. The essential problem is that such new neurons must connect to some other neurons, which in turn connect with others, etc. They cannot simply grow, they must connect ... and if they don't they will die. Furthermore, neurons also connect over long distances, so that the claim that they only connect with nearby neurons is false (though to be fair, this happens much less often than connections with nearby neurons, at least if we consider those newborn in adult life). As for a model of neurons which allows them to increase, yes, there are such models. The real issue is that of just how they increase; it's worth pointing out here that multiplication of neurons in real brains was accepted much more recently than the one model you mention. That model shows little similarity to the real workings of brains, and thus I put little weight on it. You also suggest that computer systems could be designed to be capable of self repair. The self-repair you suggest remains highly restricted in terms of what it can do. We get our own materials and process them; and to some extent (admittedly right now less in brains, but I wasn't talking only of brains) plan out just how we do that repair. We produce new neurons and their connections from materials which are not neurons. In general, our self-repair goes much farther than any machine yet built. Finally, for Turing machines, you seem to ignore the major factor of TIME. Even if everything I have said so far in this message could be rejected, the problem of the importance of TIME will remain. Each of the millions of neurons in our brain is itself a small computer, with a small memory. The reason for this is simple: a single computer does not exist that can carry out the required processing fast enough to do the job of each of these neurons ... however small and weak they may seem to be. Turing did not but should have considered TIME as a variable in his work ... but then the need for computers fast enough to solve problems in 30 minutes which would have taken millions of years for a single processor simply hadn't yet arisen. It is one thing to proposdevice capable of doing what we human beings do with our brains and feelings, and quite another to build one. That is one of the hardest issues this question raises. Sure, we can come up with very rough notions about computers which (in our thoughts alone) would allow them to do what human beings do. But when we examine them they become more and more complex, and more and more difficult, and many questions arise. The basis for believing that computers for a model for human beings comes from unexamined assumptions which deserve close examination, none of which they have received. Best and long long life for all, Thomas Donaldson Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=15319